First of all I have tried these things:
I recently received the normal updates / security patches in March to my S9 Plus and the battery has tanked. I couldn't even get a full day on normal use. I tried those things listed above and even now on a new battery, partition wipe and factory reset, I am sitting at 15% with minimal use today at 8PM. I use to get a day and a half before, but it sucks needing to look for a charger around dinner time. Is this a known issue and or should I start looking for a new phone? I really like this phone and don't really feel the need to update other than the garbage battery life.